1. Field of the Invention
The present invention relates to automotive pre-heating devices, and more particularly pertains to a new and improved automotive pre-heating device which may selectively employ AC current or DC current to insure adequate and continuous warming of an automotive interior.
2. Description of the Prior Art
The use of automotive pre-heating apparatus is well known in the prior art. These devices have undertaken a variety of configurations to enable automotive pre-heating of either an automotive interior, automotive components, or a combination of both. It may be appreciated that shortcomings of the prior art have heretofore not enabled continuous warming of an automotive interior once a user has removed an automobile proximate an auxiliary power source such as AC current supplied from a dwelling. An example of such pre-heating devices is set forth in U.S. Pat. No. 3,870,855 to Edlund. This patent discloses a combination battery charger, motor heater and passenger compartment heater, all of which are activated by a timer circuit drawing power from an outside source exclusively. This system, like others of this category, are intended to be used with auxiliary power sources only. While being a partial solution for engine compartment pre-heating as well as automotive component pre-heating, the Edlund patent does not enable the continuous warming of an automotive interior or passenger compartment until such time as engine heat may be directed to the interior thereof. Another automotive passenger pre-heating device of similar intent is to be found in U.S. Pat. No. 4,350,287 to Richards. The Richards' patent addresses the pre-heating of an automotive passenger compartment by providing a separate automotive pre-heater battery that, in this instance, may be activated by a remote transmitter arrangement. Adequate circuitry is provided that upon the appropriate engine temperature being attained to enable warming of the passenger compartment by the automotive heater itself, a thermastic switch is closed to shut the auxiliary automotive warming apparatus off. Again, the problem of continuous warming is not fully addressed in this patent as there remains a problem of maintaining auxiliary pre-heater output due to limitations of the separate battery associated therewith. A further example of automotive passenger compartment pre-heating may be found in U.S. Pat. No. 4,034,204 to Windsor. Essentially the Windsor patent is an auxiliary automotive heating device with a self-contained heating element operable through an adjustable thermostat unit to provide heat to an automotive interior. The Windsor patent, as does the entire class of patents of this category, fails to provide a means to provide continuous pre-heating of an automotive interior by initially drawing current, not from the automotive battery itself but from an auxiliary source such as AC current imparticular and subsequently DC current, from the automotive electrical circuit.
Other U.S. patents are available to provide teaching of warming of various automotive components, such as U.S. Pat. No. 3,594,547, U.S. Pat. No. 3,673,379, U.S. Pat. No. 3,835,290, U.S. Pat. No. 4,208,570, U.S. Pat. No. 4,378,486, U.S. Pat. No. 4,506,138, U.S. Pat. No. 4,520,603, and U.S. Pat. No. 4,034,204. While the aforenoted patents are each representative of automotive heating devices, there is continuing need for a new and improved automotive pre-heating device that addresses the problem of continuous warming prior to and subsequent to use of an automobile by an individual, particularly during inclement weather.